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chapter 14 +15

Terms in this set (89)

symbiosis
living together
mutualism
both parties benefit
co evolution: adapt to depend each other
example of mutualism
E. coli
commensalism
microbe benefits, host unaffected
coevolution
adapt to depend each other
tolerance
immune system does not fight non-destructive organisms
probiotic
live microbes applied to or ingested into the body, intended to exert a beneficial effect
example of commensalism
diptheroids
parasitism
pathogen always harms the host
examples of parasitism
Vibrio cholera
shigella
salmonella
virulence
measure of the amount of harm damage inflicted by the pathogen
normal microbiota
permanently colonize the host and do not cause disease under normal conditions
opportunistic infection
Infections that occur when the body's defenses are weakened
tools for invasion
-Adhesins (adhesion via fimbriae)
-IgA protease (destruction IgA on mucus)
-capsules: protect phagocytosis
-C5a peptidase: destruction of complement protein
-M protein: (prevent opsonization in strept)
-Intracellular infection (inhibit phagolysosome function)
-Antigenic variation (org changes appearance)
ID50
the number of microorganisms required to produce a demonstrable infection in 50% of the test host population
LD50
the lethal does for 50% of the inoculated hosts within a given period
exotoxins
secreted outside cell
mostly by G +
by living cells
most are proteins
have specific effects
low LD50 (ng)
example of exotoxins
botulism, tetanus, diptheria
endotoxins
part of cell wall
all by G-
form dying cells
all are lipids (LPS)
have systemic effects
high LD50 (mg)
examples of endotoxins
UTI
typhoid
meningococcal meningitis
AB exotoxins
composed of two subunits
A subunit - responsible for toxic effect
B subunit - binds to specific target cell
AB exotoxin example
diphtheria toxin
membrane disrupting toxins
lyse host cells by disrupting plasma membranes
example of membrane disrupting toxin
S. aureus
C. perfringens
superantigen
antigen which yields an exaggerated response
example of super antigen
toxic shock syndrome
Kotch's Postulates
strict chain of evident that links a specific organism with a specific disease
1. pathogen must be present in all with disease
2. pathogen must be isolated and grown in pure culture
3. cultured pathogen must cause the same disease in inoculated test animal
4. same pathogen must be isolated from inoculated animal
why are kochs postulates difficult to apply to some organisms?
some can't be isolated and they have to be grown in vivo
etiology
cause of disease
epidemiology
Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.
infectious reservoirs
natural habitat, harbors and allow the spread of pathogen
human
animals
non-living
human reservoirs
carriers may have inapparent infections or latent diseases
cold flu strep
animal reservoirs
contact transfers to humans (zoonoses)
rabies, lyme, toxo
non-living reservoirs
environmental microbes in soil or H20
botulism, tetanus
main portals of exit
doorway out of the host
respiratory
gastrointestinal
wounds
blood
urogenital
respiratory exit
in coughing, sneezing TB
gastrointestinal exit
feces or vomit
Cholera
wound exit
skin, pus, tissue
mRSA
blood exit
venipuncture, surgery, transfusions
Hep B
Urogenital exit
semen or vagina secretion
STD
portals of entry
doorway into new host
mucous membranes
parenteral rout
unbroken skin
mucous membranes entry
most common entry
all openings of body lined with mucous membranes
mouth, nose, eyes, anus, vagina, urethra
parenteral route
though break in skin
unbroken skin
rare entry thru pore or follicle
contact transmission
direct, indirect, droplet
direct contract transmission
requires physical connection
example of direct contract transmission
mono STD
indirect contract transmission
intermediate objects (fomite) like glasses, bedrails, toilets, doorknobs
example of indirect contract transmission
mRSA
Droplets contact transmission
body secretion (<1 meter) from short distance (<1 meter)
example of Droplets contact transmission
cold flu
vehicle transmission
food/ water: via contaminated water or food
blood: via contaminated blood or body fluids
airborne: carried on dry air currents > 1 meter
example of diseases through contaminate food/water
salmonella, Giardia, worms
example of diseases through contaminated blood/ fluids
Hep B/C
west nile
example of diseases through contaminated air
measles
TB
vector transmission
mechanical or biological
mechanical vector transmission
incidental, accidental transmission
example of mechanical vector transmission
flies on food
biological vector transmission
vector is required part of lifestyle
examples of biological vector transmission
malaria
lyme
plague
nosocomial infection
hospitals/ clinic acquired infections (HAI) 5-15% patients get, many die
types of microbes
types of patients
transmission
types of microbes
drug resistant, difficult to disinfect
example of types of microbes
mRSA, Pseudomonas, Enterococci, C. diff
types of patients
immunocompromised by illness, surgery, drugs, anesthesia, depression, ect.
transmission
invasive procedures
example of transmission
surgery, catheters, respiratory, IV
the top nosocomial bacteria
AIDS 1993
John snow
cholera
Ignaz Semmelweis
hand washing
Florence nightingale
typhus
clean linens
modern epidemiological agencies
CDC (center for disease control)
NIH (national institute of health)
WHO (world health organization)
index case
the first patient found in an epidemiological investigation
notifiable diseases
HIV/ AIDS
TB
measles
meningitis
hepatitis
gonorrhea
leprosy
EIDs
new disease or old diseases with increasing incidence or virulence
microbial evolution
human behavior
political upheaval and war
climate change and natural disasters
development into remote areas
global trade and travel
incidence
the fraction of the population that contracts a disease during a particular period of time
prevalence
the fraction of a population having a specific disease at a given time
sporadic
occurs occasionally in a population
endemic
confined to a particular country or area
epidemic
A widespread outbreak of an infectious disease.
pandemic
Disease that occurs over a wide geographic area and affects a very high proportion of the population.
bacteremia
presence of bacteria in the bloodstream
septicemia
growth of bacteria in the blood
viremia
viruses in the blood
toxemia
toxins in the blood
prodromal
early symptoms that may indicate the onset of a condition or disease
incubation
process to develop an infection
convalescence
gradual recovery after an illness
systemic infection
an infection throughout the body
secondary infection
opportunistic infection after a primary infection
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